When sound frequencies are played through water, the sound waves create certain patterns depending on the frequency. We wanted to see what would happen if we did the same thing, but with a Non-Newtonian fluid instead of water. A Non-Newtonian fluid is a fluid that does not have a constant flow rate. The Non-Newtonian fluid that we used was a mixture of cornstarch and water, more commonly known as “oobleck.” The flow rate of oobleck depends on the stress that it endures. For example, when you move your finger gently through it, the oobleck acts like a liquid, but if you smack it with your hand, it acts like a solid. The molecules of the cornstarch are very closely packed together, and when they are combined with water, the water molecules fill in the gaps between the cornstarch molecules. When force is applied to the mixture, the water is pushed out from in between the cornstarch molecules, and the mixture becomes a solid. Oobleck’s unique properties cause it to come “alive” when sound waves are played through it. We wanted to figure out how the frequency and volume of the sound waves affected the oobleck’s reaction.
Procedure
For the experiment, we took a speaker out of it's casing and connected it to a computer. Then, we glued a plastic container to the center of the speaker and filled it with 40 ml of water and 80 ml of cornstarch. We made quarter-inch marks on the side of the container starting at the water level to measure how high the fluid went. We played each frequency for 20 seconds. We set up a camera next to the speaker and played back each test in slow motion to determine the maximum height. We played a tone at frequencies 10-150 Hz at 10 Hz intervals, and had the volume at both max, and ¾.
Results
3/4 volume
Frequency (hz)
Height (in)
10
0
20
2
30
1.5
40
1.25
50
0.5
60
0.3
70
1
80
1
90
0.75
100
0.66
110
0.5
120
0.33
130
0.33
140
0.06
150
0.375
Full volume
frequency (hz)
height (in)
10
0.1
20
1.75
30
2
40
1.75
50
1
60
1
70
0.75
80
0.66
90
0.75
100
0.5
110
0.5
120
0.15
130
0.1
140
0.1
150
0
Conclusions
Based on the data we receive, we came to the conclusion that both volume and frequency affected how the mixture reacted. With higher frequencies, the max height was significantly lower, and it seemed to bubble more than anything. From our observations, volume mainly affected data consistency. As you can see from the ¾ volume graph, there is a dip around 55 Hz. If this experiment were to be redone, I think that one thing that could have been improved would be to find a more accurate way to detect the max height of the liquid. Something that could be looked into more would be why the max height dips around 55 Hz.
Table of Contents
Cornstarch and Water with Subwoofer
Drew, Coleman
Introduction
When sound frequencies are played through water, the sound waves create certain patterns depending on the frequency. We wanted to see what would happen if we did the same thing, but with a Non-Newtonian fluid instead of water. A Non-Newtonian fluid is a fluid that does not have a constant flow rate. The Non-Newtonian fluid that we used was a mixture of cornstarch and water, more commonly known as “oobleck.” The flow rate of oobleck depends on the stress that it endures. For example, when you move your finger gently through it, the oobleck acts like a liquid, but if you smack it with your hand, it acts like a solid. The molecules of the cornstarch are very closely packed together, and when they are combined with water, the water molecules fill in the gaps between the cornstarch molecules. When force is applied to the mixture, the water is pushed out from in between the cornstarch molecules, and the mixture becomes a solid. Oobleck’s unique properties cause it to come “alive” when sound waves are played through it. We wanted to figure out how the frequency and volume of the sound waves affected the oobleck’s reaction.
Procedure
For the experiment, we took a speaker out of it's casing and connected it to a computer. Then, we glued a plastic container to the center of the speaker and filled it with 40 ml of water and 80 ml of cornstarch. We made quarter-inch marks on the side of the container starting at the water level to measure how high the fluid went. We played each frequency for 20 seconds. We set up a camera next to the speaker and played back each test in slow motion to determine the maximum height. We played a tone at frequencies 10-150 Hz at 10 Hz intervals, and had the volume at both max, and ¾.
Results
3/4 volume
Full volume
Conclusions
Based on the data we receive, we came to the conclusion that both volume and frequency affected how the mixture reacted. With higher frequencies, the max height was significantly lower, and it seemed to bubble more than anything. From our observations, volume mainly affected data consistency. As you can see from the ¾ volume graph, there is a dip around 55 Hz. If this experiment were to be redone, I think that one thing that could have been improved would be to find a more accurate way to detect the max height of the liquid. Something that could be looked into more would be why the max height dips around 55 Hz.
References
Wisegeek. "what is a non newtonian fluid." WiseGeek. N.p., 13 Dec. 2009. Web. 28 Jan. 2010. <http://www.wisegeek.com/what-is-a-non-newtonian-fluid.htm >.http://en.wikipedia.org/wiki/Non-Newtonian_fluidhttp://blog.makezine.com/archive/2009/08/collins_lab_notes_diy_cymatics.html